Formation of martensitic microstructure in epitaxial Ni-Mn-Ga films after fast cooling

Fuente: arXiv
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Main Authors: Ge, Yuru, Ganss, Fabian, Lünser, Klara, Kar, Satyakam, Hübner, René, Zhou, Shengqiang, Rebohle, Lars, Fähler, Sebastian
Format: Preprint
Published: 2024
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author Ge, Yuru
Ganss, Fabian
Lünser, Klara
Kar, Satyakam
Hübner, René
Zhou, Shengqiang
Rebohle, Lars
Fähler, Sebastian
author_facet Ge, Yuru
Ganss, Fabian
Lünser, Klara
Kar, Satyakam
Hübner, René
Zhou, Shengqiang
Rebohle, Lars
Fähler, Sebastian
contents Shape memory alloys have a wide range of applications, including high stroke actuation, energy-efficient ferroic cooling, and energy harvesting. These applications are based on a reversible martensitic transformation, which results in a complex microstructure in the martensitic state. Understanding the formation of this microstructure after fast heating and cooling is crucial, as a high cycle frequency is essential for achieving high power density in the mentioned applications. This article uses an epitaxial Ni-Mn-Ga film as a model system to study the formation of the martensitic microstructure, since the high surface-to-volume ratio of thin films enables rapid heating and cooling, and since the formation of a multi-level hierarchical microstructure during slow cooling of this material system is already well understood. We apply a millisecond flash lamp pulse of varying energy density on the Ni-Mn-Ga film and analyse the hierarchical martensitic microstructure afterwards. Substantial differences compared to slow cooling occur, which we attribute to the limited time available for the microstructure to form and to the thermal stress between film and substrate during rapid temperature changes.
format Preprint
id arxiv_https___arxiv_org_abs_2409_20226
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Formation of martensitic microstructure in epitaxial Ni-Mn-Ga films after fast cooling
Ge, Yuru
Ganss, Fabian
Lünser, Klara
Kar, Satyakam
Hübner, René
Zhou, Shengqiang
Rebohle, Lars
Fähler, Sebastian
Materials Science
Shape memory alloys have a wide range of applications, including high stroke actuation, energy-efficient ferroic cooling, and energy harvesting. These applications are based on a reversible martensitic transformation, which results in a complex microstructure in the martensitic state. Understanding the formation of this microstructure after fast heating and cooling is crucial, as a high cycle frequency is essential for achieving high power density in the mentioned applications. This article uses an epitaxial Ni-Mn-Ga film as a model system to study the formation of the martensitic microstructure, since the high surface-to-volume ratio of thin films enables rapid heating and cooling, and since the formation of a multi-level hierarchical microstructure during slow cooling of this material system is already well understood. We apply a millisecond flash lamp pulse of varying energy density on the Ni-Mn-Ga film and analyse the hierarchical martensitic microstructure afterwards. Substantial differences compared to slow cooling occur, which we attribute to the limited time available for the microstructure to form and to the thermal stress between film and substrate during rapid temperature changes.
title Formation of martensitic microstructure in epitaxial Ni-Mn-Ga films after fast cooling
topic Materials Science
url https://arxiv.org/abs/2409.20226